ash: Start/stop observing KeyboardController via ShellObserver

ash/shell.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/shell.h"
 
 #include <algorithm>
 #include <string>
 #include <utility>
 
@@ skipping 437 matching lines @@
                                          WmWindow* root_window) {
   for (auto& observer : shell_observers_)
     observer.OnFullscreenStateChanged(is_fullscreen, root_window);
 }
 
 void Shell::NotifyPinnedStateChanged(WmWindow* pinned_window) {
   for (auto& observer : shell_observers_)
     observer.OnPinnedStateChanged(pinned_window);
 }
 
-void Shell::NotifyVirtualKeyboardActivated(bool activated) {
+void Shell::NotifyVirtualKeyboardActivated(bool activated,
+                                           WmWindow* root_window) {
   for (auto& observer : shell_observers_)
-    observer.OnVirtualKeyboardStateChanged(activated);
+    observer.OnVirtualKeyboardStateChanged(activated, root_window);
 }
 
 void Shell::NotifyShelfCreatedForRootWindow(WmWindow* root_window) {
   for (auto& observer : shell_observers_)
     observer.OnShelfCreatedForRootWindow(root_window);
 }
 
 void Shell::NotifyShelfAlignmentChanged(WmWindow* root_window) {
   for (auto& observer : shell_observers_)
     observer.OnShelfAlignmentChanged(root_window);
@@ skipping 598 matching lines @@
 void Shell::OnWindowActivated(
     aura::client::ActivationChangeObserver::ActivationReason reason,
     aura::Window* gained_active,
     aura::Window* lost_active) {
   WmWindow* gained_active_wm = WmWindow::Get(gained_active);
   if (gained_active_wm)
     root_window_for_new_windows_ = gained_active_wm->GetRootWindow();
 }
 
 }  // namespace ash